1. Technical Field
The present invention relates to a wireless communication system in which data is wirelessly transmitted and received.
2. Related Art
In related art, such a technique that can establish synchronization between first and second networks is known. The first and second networks each is configured by a plurality of mobile wireless communication units that perform wireless communication (see, for example, patent document JP-B-4763334). In the technique, a synchronization device, which transmits synchronous signals, is set up in advance at a position from which synchronous signals can reach both of the first and second networks.
JP-B-4763334 discloses a wireless ad-hoc communication system in which a plurality of terminals mutually transmit and receive a first beacon so that these terminals can be synchronized. The wireless ad-hoc communication system has a first network to which a first group of terminals of the terminals belongs, and a second network to which a second group of terminals of the terminals belongs. At least one synchronization terminal is arranged in advance in a region where the terminals can be mobile. The synchronization terminal is able to receive the first beacon, while also being able to transmit a second beacon generated by itself to the terminals.
When the terminals belonging to the first and second groups reside in a range to which the second beacon transmitted by the synchronization terminal can reach, one synchronized network is formed, which includes the first and second networks and the synchronization terminal. Thus, a plurality of wireless ad-hoc communication networks that cannot directly transmit and receive a beacon can be synchronized with the intervention of the synchronization terminal.
However, with the technique described in JP-B-4763334, a synchronization terminal is required to be set up in advance and the range in which synchronization can be established is limited to the range to which synchronous signals are reachable. Therefore, it is difficult to apply this technique to an inter-vehicle communication system, for example, which is configured by wireless communication units that could be mobile on a widespread scale.